I don't know how well flashbulbs hold up with time. I think
these are probably gas filled bulbs. They will have an igniter on
the filament support, looks like gray drops. I would shoot at
half speed. Safe anyhow since B&W ISO film speeds are about the
maximum for any shadow detail, usually safe to overexpose by a
stop and often results in better tone rendition.
Medium and slow bulbs have shreded foil in them. This is
usually a mixture of magnesium and aluminum. Very old (1930s)
bulbs have crumpled aluminum foil in them. They are collector's
items. Sylvania lamps, also sold as Wabash, have a blue dot on
the end. If the dot is blue the bulb is OK if pink its not. I
think I once knew what this was but don't remember.
I will be very interested in your results.
On 9/10/2019 7:21 PM, CarlosMFreaza wrote:
Richard:
I could read in the bulbs box the guide number is 30 for ISO 100 film and the bulbs light lasts 1/250 sec, but I doubt these specs are right after decades, I hope the bulbs work at least, I'll see. Thank you Richard.
Carlos
El mar., 10 de sep. de 2019 19:26, `Richard Knoppow <dickburk@xxxxxxxxxxxxx <mailto:dickburk@xxxxxxxxxxxxx>> escribió:
If the bulbs were in a sleeve it probably has exposure
instructions on it. Otherwise you may be able to find the
exposure charts on line. The only flash information I have is in
old editions of the "Photo Lab Index" which has U.S. made bulbs
in it. Unlike strobe flash where the shutter speed makes little
difference it can have a large effect on bulbs. However, Class-X
lamps usually have a very short dwell time, short enough to stop
some motion.
Flash bulbs have a different quality of light from strobe,
sometimes a bit subtle.
I will be interested to see the results.
On 9/10/2019 3:13 PM, CarlosMFreaza wrote:
> . Last week I received two 22,5v alkaline batteries
for the
> Rolleiflash 1 from England and this morning five Osram
Vacublitz
> XP flash bulbs new old stock from Buenos Aires city. I put
the
> battery into de flash body and the bulb according the
> instructions and I became almost amazed when I pressed the
button
> for the little green test lamp: it worked¡, it flashed as the
> instructions describe. It means the circuit is working
fine, no
> capacitor problems.Now I`'ll read more info about this bulb
> features, the box has minimal instructions, they work with X
> contact. You feel you come back decades to the past handling
> these elements, a pleasant sensation to me.-
> Carlos
>
